Torch for the subaqueous cutting of metals



June 13, 1950 w. 1". P. KIRKHAM TORCH FOR THE SUBAQUEOUS CUTTING OF METALS Filed June 28, 1946 Mar e rP/melo/wz W1 flzmen sr Patented June 13, 1950 TORGH FOR THE SUBAQUEOUS "CUTTING- F META-Ls Walter Thomas Patrick Kirkham, Southwick, near Brighton, England Application June 28, 1946, ESeriaI No. 80,162 In Great Britain July 3 .1945

3 Claims. 1 This invention relates tometal-cutting torches oi the kind in which the base of'the flameis'protected by means of a shield arranged to create a gas pocket round the burner nozzle so as to enable the torch to be used under water.

In torches of this kind .at present in use, the cavity between the .s'hieldand the "burner nozzle is supplied with air or oxygen under pressure through a port or tube connected to a special flexible conduit for supplying air or oxy en to the shield. Thu-stile shieldnot only increases the gas consumption'of the torch but increases the number of flexible conduits and associated supply apparatusrequired.

By the present invention, a shield is provided which doesnot require to be supplied with oxygen or air under pressure and the equipment hitherto necessary for supplying this air or oxygen is thus dispensed with.

According to the invention, this result is achieved by arranging the opening in the shield through which the flame emerges so that a small proportion of the gas in the jet supplying the flame is deflected into the shield cavity so as to expel water from the cavity and to maintain a sulficient pressure of gas round the base of the flame to enable it to burn under water. Advantageously, the shield is shaped so that the inner wall surface of the shield immediately surrounding the aperture is a flat surface set at rightangles to the axis of the burner and thus pro-' vides a ledge, the diameter of the aperture being so chosen that a small proportion of the gas mixture issuing from the burner nozzle impinges on the ledge and is deflected or passes into the shield cavity without either unduly high gas pressure or high gas speed. Previous inventions of a similar nature have obtained partial results by relying on a high speed in conjunction with the natural expansion of the gases leaving the burning nozzles. The high speed referred to has been obtained by using high pressure; furthermore, no saving in supply accessories was effected owing to this high pressure being out of proportion, in deep Water, to the cutting line requirements, which in turn required a separate source of supply.

Unlike previous types, the pressure required to the two supply pipes need never exceed the pressure required to cut in air plus the pressure accepted and known for whatever depth of water in which cutting is to take place. In point of fact, it would appear that the above formula gives a pressure in excess of requirements.

One form of the invention isillustrated in the accompanying drawings, in which:

Figure 1 is a sectional view of part of the nozzle of ,a cutting torch ,fitted with a shield according to'thefinventiomand ,FigureZ isanend view of the same.

In the drawing, 1 indicates the annular nozzle through which a jet ofcombustible mixture is supplied to the flame andlindicates the central nozzle through which the flame .is supplied with cutting oxygen when required. These nozzles may be constructed, for example, as, described in the specifications of my .copending British Pat- .ent App ications Nos. 19,434 and 19,435 of 1945, or they m y b any kn w or p e e e struction.

Screwedyor otherwise secured to the bod of "the nozzle l is .a shield} arranged to surround ithe nozzles 1 andz so as to form a shield cavity 4 between the shieldandthe nozzle]. The shield telescopically fits cover the ,outer nozzle and its end wall extends a short distancebQYDnd the tip of the nozzle l and isiormed with an aperture 5 in alignment with the nozzle, through which aperture the flame emerges when the torch is in use. The shield is shaped so that the inner wall surface of the shield immediately surrounding the aperture forms a flat annular ledge 6 at rightangles to the axis of the burner. The diameter of the aperture 5 is so chosen that a small proportion of the mixture emitted from the nozzle I impinges on the shoulder or ledge 6 and is deflected into the shield cavity 4. To obtain this result it will ordinarily be found advisable to make the diameter of the aperture 5 slightl less than the outside diameter of the orifice through which the mixture emerges from the nozzle I. The diameter required for the aperture 5, however, may vary somewhat with different types of burner nozzle; the diameter of shield aperture for use with a given design of burner nozzle is best determined by trial and error, the optimum diameter being that which is just large enough to avoid burning of the shield when tested under working conditions.

The outer surface of the end of the shield is countersunk round the aperture 5 and is formed with a number of grooves 1 which increase in width and depth from the centre to the periphery of the shield end surface; the metal separating these grooves forms a number of radial flutes 8 for spacing the shield from the work and allowing the flame gases to escape through the grooves 1.

In use, under water, the burner is thrust 3 against the work in the usual manner so that the ribs 8 make contact with the work. The grooves 1 provide a way of escape for the flame gases and the countersink round the aperture 5 assists in the concentration and even distribution of the flame. The small quantity of gaseous mixture which is deflected or passes into the shield cavity and is temporarily held by the ledge 6, drives water out of the shield cavity and maintains a suificient pressure of gas round the base of the flame to protect the same from the water and allow the burner to operate eflective- 1y. No separate supply of air or oxygen under pressure to the shield cavity is required. The need for a special shield supply line and the accessories appropriate thereto is thus avoided. Also, by means of the present invention the aperture in the shield controls the flame sizeso as to prevent excess burning and undesirable spread of the flame when preheating the work. An even distribution of the flame and gas is obtained by the countersinking and the flutes on the end of the shield. The burner can be lighted in all depth of water.

Although my shield is designed to operate without being fed with air'or oxygen under pressure, the shield cavity may, if desired, be connected to the conduit that supplies oxygen for combustion so that a small supply of oxygen at a pressure exceeding the static head of water is admitted to the shield cavity.

I claim:

1. A torch comprising an annular nozzle, a central nozzle mounted within said annular noz- 21s, a shield aflixed with its rear portion to said annular nozzle to form therewith a gas pocket closed at its rear end, means carried by said shield providing a passage for a larger part of the gas emitted from said annular nozzle and deflecting a smaller part of the gases into said pocket, said passage having a countersunk outer part,'and a plurality of flutes radiating from the outer end of said countersunk passage.

2. A torch, comprising, an annular outer no'zzle, a central nozzle mounted within said outer annular nozzle, a shield telescopically mounted on said outer nozzle and having an end wall spaced forwardly from the face and adjacent side portions of said annular nozzle to provide a gas cavity surrounding the tip of the outer nozzle, a shoulder surounding an aperture in the shield said aperture being of less diameter than the opening in the annular outer nozzle and arranged c'oaxially with said annular and central nozzles to provide a passage for emitting the bulk of said ases from said annular nozzle and said shoulder deflecting a portion of said gases into the cavity to build up gas pressure to keep water away from the mouth of the outer nozzle and protect the base of the flame issuing therefrom.

3. A torch for the subaqueous cutting of metals, comprising, an annular nozzle having an orifice, a central nozzle mounted within the orifice of said annular nozzle and having its inner wall spaced forwardly from the face and adjacent side portion of said annular nozzle to provide a shallow annular gas cavity extending forwardly of the face of the nozzle and rearwardly thereabout, the end of said shield having an aperture of less diameter than the orifice of the annular nozzle to provide a shoulder for deflecting a portion of the gases into the cavity to maintain gas pressure in said cavity to exclude water therefrom and protect the base of the flame against extinguishment.

WALTER THOMAS PATRICK KIRKHAM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 

